The mode of a set of data is the value that appears most frequently. In other words, it is the number that occurs with the highest frequency within a given dataset.
To find the mode, you simply count how many times each value appears. If a value occurs more than any other, that is the mode. In some cases, a dataset might have multiple modes if two or more values appear with the same highest frequency; such datasets are referred to as multimodal. Conversely, if all values occur with the same frequency, the dataset is said to have no mode.
For example, consider the dataset: {1, 2, 2, 3, 4}. Here, the number 2 is the mode because it appears twice, more often than any other number.